1. Field of the Invention
The present invention relates to a semiconductor device and a manufacturing process thereof. More particularly, the present invention relates to a semiconductor device in which the reliability of the electrical connection between the device and other electronic devices is enhanced and a manufacturing process of the semiconductor device.
2. Description of Related Art
Flip chip interconnect technology is a type of packing technology that provides a connection of a die to a printed circuit board, wherein a plurality of bumps is formed on a plurality of contacts on the die. The die is then flipped over, and the bumps are connected to the terminals on the printed circuit board to electrically connect the die to the printed circuit board via the bumps.
FIGS. 1A to 1C are schematic, cross-sectional views showing the steps for fabricating a bump on a contact of a die according to the prior art. As shown in FIG. 1A, a die 110 is first provided, wherein the die has an active surface 112. The die 110 also has a plurality of contacts 114, disposed on the active surface 112. A protective layer 120 is further formed on the active surface 112.
Continuing to FIG. 1B, subsequent to a photolithography/etching process, a plurality of openings 122 is formed in the protective layer 120, wherein these openings expose the contacts 114. It is worthy to note that the size of the openings 122 is smaller than the contacts 114. Accordingly, the protective layer 120 at the vicinity of each opening 122 has a protrusion P. A layer of under bump metallurgy (UBM) material 150 is formed on the protective layer 120 and the contacts 114. A photoresist layer 130 is then formed on the UBM material 150. Subsequent to a photograph/etching process, a plurality of openings 132 is formed in the photoresist layer 130, wherein these openings 132 expose the UBM material 150 at where the contacts 114 are disposed. Subsequent to electroplating gold in these openings, a plurality of gold bumps 140 is formed on the die 110, wherein these gold bumps 140 are electrically connected to the contacts 114 through the UBM material 150.
Continuing to FIG. 1C, the photoresist layer 130 is removed. Further using these bumps 140 as a mask, the UBM material 150 not covered by the gold bumps 140 is removed to form a die structure 100 having a plurality of gold bumps 140. It is also worthy to note that the region covered by the gold bump 140 also includes a ring of protrusion P on the protective layer 120. Accordingly, the gold bump 140 also includes a ring of protrusion Q, corresponding to the ring of protrusion P on the protective layer.
Referring to FIG. 2, FIG. 2 is schematic, cross-sectional view showing the convention fabrication method of a bump on a die that is electrically connected to a printed circuit board. Accordingly to the conventional technique, the printed circuit board 200 is electrically connected to the die 110 through an anisotropic conductive film (adhesive) 250 and a gold bump 140, wherein the anisotropic conductive film 250 has a plurality of granules 252 having a conductive interior and an insulating exterior. The printed circuit board 200 has a plurality of terminals 210.
When the printed circuit board 200 is electrically connected to the die 110 through the anisotropic conductive film 250 and the gold bumps 140, some of the granules 252 are pressured by the protrusion Q on each gold bump 140 and the terminals 210. The insulating exterior of the granules 252 at where pressure is being applied is fractured by the protrusions Q on the gold bumps 140 and the terminals 210 for the die 110 exposing the conductive interior. As a result, the conductive interior of the granules 252 can electrically connect to the protrusion Q and the terminals 210 through the fracture site of the insulating exterior in order for the die to electrically connect to the printed circuit board 200.
It is also important to note that the surface area of the protruded region Q of the gold bump 140 is very small. Using the conventional technique to electrically connect the gold bump 140 to the contact pad 210 via the anisotropic conductive film 250, the reliability of the electrical connection between the gold bumps 140 and the terminals 210 is lower.